Embodiments of the inventive concept generally relate to image processing, and more particularly, to methods and devices for removing color fringe in a narrow color region of a digital image.
When a digital camera captures a color image of a live scene, a lens of the camera may not focus all colors to a convergence point. As a result, distortion may occur near boundaries of objects in the color image. This distortion is referred to herein as color fringe. Color fringe can become especially problematic as the resolution of the color image is increased or when the digital camera is relied on for detailed imagery.
Generally, color fringe results from chromatic aberration (color distortion) caused by an optical system and by a blooming effect. First, with respect to the optical system, chromatic aberration can result when RGB colors of light are not focused at a single point at the same time through a lens. That is, since the refractive indexes of the RGB colors differ from each other according to a wavelength, components of the three colors passing through a lens may not be focused on the same axis or plane.
Second, with respect to the blooming effect, when a bright color is passed through an image sensor pixel for a continuous amount of time, accumulated charges may overflow into a potential wall. The overflowing charges may transfer to neighboring pixels, thereby causing color artifacts including a near-saturation region.